Groundwater Flow Modeling: A Case Study of the Lower Rusizi Alluvial Plain Aquifer, North-Western Burundi (original) (raw)

Numerical Groundwater Flow Modeling of Dijil River Catchment, Debre Markos Area, Ethiopia

Momona Ethiopian Journal of Science, 2021

Dijil River catchment is a sub-catchment of the Abay drainage basin and covers 138.28 km2. This paper presents numerical groundwater flow modeling at steady-state conditions, in a single-layer aquifer system under different stress or scenarios. A numerical groundwater flow models represent the simplification of complex natural systems, different parameters were assembled into a conceptual model to represent the complex natural system in a simplified form. The conceptual model was input into the numeric model to examine the system response. Based on geologic and hydrogeological information, confined subsurface flow condition was considered and simulated using MODFLOW 2000. The model calibration accounts matching of 24 observation points with the simulated head with a permissible residual head of ±10m. The sensitivity of the major parameters of the model was identified during the calibration process. According to the simulated water budget in the model, the simulated inflow is found t...

Groundwater Flow Modeling in the Coastal Aquifer of Bosaso Plain, Somalia

INTERNATIONAL CONFERENCE ON LIFE AND ENGINEERING SCIENCES,(ICOLES), 2019

Groundwater is one of the world's main sources of drinking water. Groundwater is the major source of drinking water of the Bosaso city. Due rapid increase of population in the city the use of groundwater supplies has grown over time and created concern about the quality and quantity of water available. The groundwater flow models can be used to predict the effects of the external stresses applied on aquifer system for risk evaluation and management purposes in the city. This study presents the development of conceptual and numerical model for groundwater flow in the Bosaso Plain. For this purpose, one-layer coastal aquifer was conceptualized. The model was calibrated using Parameter Estimation (PEST) the root mean square (RMS) and the correlation coefficient () was used as model evaluation criteria. A good match between the observed and simulated head was obtained with value 0.97 and 7.6 % for and RMS respectively. This developed model could be used for further groundwater modelling studies.

Groundwater flow simulation in the Tymbaki aquifer by using different subsurface geological models

16th International Congress of the Geological Society of Greece 17-19 October, 2022 - Patras, Greece Bulletin of the Geological Society of Greece, Sp. Publ. 10 Ext. Abs. GSG2022-137, 2022

Groundwater resources in Mediterranean coastal aquifers are under threat due to overexploitation of the water resources. Efficient management and monitoring of groundwater systems require interpreting all available data sources. Geostatistics and geophysics can be successfully combined to interpretating the hydrogeological characteristics of an aquifer system. This work is based on geological and geophysical surveys held in the coastal alluvial aquifer of the Tympaki basin in the south and central part of the island of Crete, Greece. This research work aims to develop a set of plausible 3D geological models combining data of geological maps and mapping, 1D and 2D geophysical profiles, spatial well data analytics, and geostatistical simulation techniques. The resulting set of models represents possible scenarios of the structure of the coastal aquifer system under investigation and identify regions associated with higher uncertainty. Management and monitoring of groundwater systems require a sufficient understanding of hydrogeology and the subsurface configuration. This work employs the development of a 3D geological model by using two different approaches to assess the impact that each one has on the groundwater flow simulation. The first approach is based on geophysical data using geostatistical and simulation techniques such as 3D Kriging and Sequential Gaussian Simulation (SGS) to provide the structure of the coastal aquifer system. A geophysical survey (Pipatpan and Blindow 2005) provided data in the study area that were inverted to hydraulic conductivity. Therefore, the inverted geophysical data were used to estimate the spatial distribution of the hydraulic conductivity in the study area. The modified Box–Cox technique was applied to transform the data close to normal distribution to allow the application of the SGS method. SGS is a stochastic approach for producing equiprobable realizations (maps) of spatial distribution of a variable on a grid by means of kriging methodology. Variogram analysis was employed to investigate the spatial dependence of the monitoring data, while the simulation analysis provided the spatial distribution of hydraulic conductivity considering the bounds of estimations uncertainty. The second approach uses the lithostratigraphic interpretation of the available geophysical and water-well data to define the subsurface structure of the alluvial aquifer and the associated fault patterns (Panagopoulos et al., 2021). Then, the geological model is further populated with resistivity and lithological values by applying stochastic algorithms of gaussian random function simulation and the sequential indicator simulation, respectively (Schlumberger, 2016). Finally, the two approaches were combined to run a new groundwater flow simulation and assess the benefits of using a more detailed subsurface geological model as the basis for the simulation. The proposed methodologies exploit the spatial information from geophysical surveys to provide the spatial distribution of the hydrogeological structure of the coastal aquifer system in three dimensions inside the convex hull of the measurements. The resulting models will be imported under the same parameterization (e.g., boundary conditions) to a numerical groundwater flow model (Feflow), considering time series of groundwater level in 20 monitoring wells and 6 observation wells for validation, to determine the groundwater level field in the study area. The 3D property distribution of hydraulic conductivity, resistivity and lithologies have been constructed to understand the aquifer’s behavior better. The property model helps to identify the areas where the coarser material is expected as well as areas of low resistivity that could be related to seawater intrusion. Comparing the two approaches will help identify similarities and differences in groundwater flow modeling using different data interpretation tools. In addition, it will provide valuable information on the hydrogeological structure detail which is required to acquire optimal groundwater flow modelling results. Such approaches can help develop typical hydrogeological models, which will aid the management and monitoring of the area's groundwater resources. This work will support the development of a reliable groundwater flow model to investigate future groundwater level fluctuations in the study area under climate change scenarios. References Panagopoulos, G.; Soupios, P.; Vafidis, A.; Manoutsoglou, E.: Integrated use of well and geophysical data for constructing 3D geological models in shallow aquifers: a case study at the Tymbakion basin, Crete. Greece. Environm. Earth Sci. 80, 142 (2021).

Groundwater Prospects in Kirundo District , Northern Burundi : Modeling by Remote Sensing and Gis

2018

The importance of groundwater is growing due to the rising demand in the Kirundo District northern part of Burundi and Remote Sensing (RS) and Geographic Information System (GIS) have come as a set of modern tools in the investigation/identification of the Groundwater potential zones an important bounty of Groundwater. The input data for this study included Geology, lineaments, drainage density, land use/land cover, soil cover, and nature of landscape and distribution of land-surface slope. RS data products used are Landsat TM image, viz., TM 5– 4-3 as well as ASTER G DEM of 30 m resolution. A groundwater prospect map is produced by integrating thematic maps, viz., geology, lineament density, drainage density, land use/land cover, soil and slope maps. The groundwater prospect zones of Kirundo district was found to be very good (7.82 km), good (80.45 km), moderate (107.17 km), low (421.58 km), poor (360.07 km), respectively 1, 8, 11, 43 and 37% of the study area. Based on this invest...

Modelling Groundwater Flow of the Besease Inland Valley Bottom in Ghana

2013

The harsh climate, shallow and erodible soils of low fertility uplands have led to farmers extending their cultivable areas to wetlands for optimal crop production since these systems have the potential for irrigation in the dry season. Inland valleys have been cited as having high potential for development of rice-based, small-holder farming systems at the village level, due to their specific hydrological conditions and relatively high soil fertility. This paper applies a 3D groundwater flow model, PM-WIN MODFLOW to simulate the groundwater heights of the two layered alluvial aquifer of the Besease Inland Valley Bottom. Groundwater recharge estimates from the watertable fluctuation method was used as the recharge input into the model. The results showed that groundwater levels ranged from 259.10-259.97 m in the wet season and 258.19 -258.86 m in the dry season for the simulation period. It also exhibited a form of interaction between the inland valley wetland and the bordering Oda ...

Analysis of Groundwater Flow Modelling: The Case of Hormat-golina Sub-basin, Golina Basin, Ethiopia

Hydrology, 2021

Analysis of the Groundwater flow can help to understand future water potential. This study has explored the predicted groundwater flow dynamics with climate change and anthropogenic stress in Hormat-Golina Sub-basin. Groundwater flow modeling in this Sub-basin has provided information about groundwater quantity as well as the quality aspect for decision-makers about groundwater accessibility. The initial head measured values before and after irrigation season has varied to a maximum of 0.8 m. The groundwater head level before and after irrigation season was varying from 9.3 m to 8.26 m in the Southern boundary. The groundwater head was obtained from 41.5 m to 38.83 m in the northwestern of the Sub-basin. The maximum drawdown depth had found to 0.27 m and 2.6 m before and after irrigated season around the pumped wells. The increased pumping rate with decreased recharge rate was replying to the groundwater head at the end of 2021 decreased by 2.81 m in the northwestern boundary of the...